According to this map, the Tang Dynasty was mostly located in northern and eastern China.
The Tang dynasty was the successor of the Sui dynasty and predecessor of the period of the Five Dynasties and the Ten Kingdoms in China. The dynasty was interrupted by the second Zhou Dynasty (690-705), when Empress Wu Zetian usurped the throne and founded her own dynasty. The Tang dynasty, with its capital in Chang'an (present-day Xi'an), the most populous city in the world at that time, is considered by historians as a moment of splendor of Chinese civilization, equal to -or even superior- to of the Han period.